Reproducibility of body volume assessments in survival clothing in fixed and portable scanning systems.

The recent development of portable 3D scanning systems for industries such as animation and museum artefact digitisation have considerable potential for applications involving human body measurement. However, this requires a system for validation of measurements against a criterion, which this study aimed to provide. Forty four adult males were scanned in duplicate in both a fixed Hamamatsu and portable Artec L scanning systems in two postures and two different clothing assemblages. Following inspection of all scans, complete data for duplicate scans of 38 participants were available for the study. Both scanners demonstrated good precision, however significant differences in body volume prevailed for both egress and scanner postures in form-fitting clothing and the scanner posture in survival suit scans, with the Hamamatsu providing greater volumes than the Artec system (by 2.7, 2.8 and 2.1 litres respectively). Regression analysis indicated the results from the portable scanner explained between 96 and 98% of the variability in the results from the fixed scanner. The biases in body volume probably relate to different software approaches to its calculation, and a possible interaction with posture and clothing. Validation of the Artec against the Hamamatsu system provides valuable information for its use in field and industrial settings

Volumetric and space requirements of the offshore workforce: the effects of donning a survival suit.

Confined space working is common place within the offshore oil and gas infrastructure and it is a persons absolute size that governs their fit within this built environment. The design and adjustability of the environment must be based on the assumed size of the workforce; 95th percentile of the male size. The last anthropometric survey of the offshore workforce was conducted almost 30 years ago and since then the average weight of the workforce has increased by 19%; although the size and shape change associated with this increase remains unknown. With advances in portable 3D scanning technology and its potential for anthropometric measurement; this study aimed to quantify the volumetric and space requirements of the offshore workforce and size increases associated with donning personal protective equipment. Forty-three male participants were measured using both a static Hamamatsu and a portable Artec L 3D scanner in three different clothing assemblages. Volumetric and linear measures indicated a 71.3% increase in total body volume and a 101.9% gain in space requirements associated with donning a survival suit. Size increases due to survival clothing was found to have a close relationship with BMI; smaller individuals increase in body volume and space requirements more than their larger counterparts, r = 0.815 and r = 0.659 respectively. This pilot study identifies a need for further research into space requirements, especially in confined spaces and using specialist clothing

Shape change and obesity prevalence among male UK offshore workers after 30 years: new insight from a 3D scanning study.

In 1984, male UK offshore workers had higher fat content and greater overweight- and obesity prevalence than the general population. Since then, body weight has increased by 19%, but - without accompanying anthropometric measures - their size increase, current obesity, and fatness prevalence remain unknown. This study therefore aimed to acquire contemporary anthropometric data, to profile changes since the original survey, and to assess current obesity prevalence in the male offshore workforce. A total of 588 men, recruited via quota sampling to match the workforce weight profile, underwent stature, weight, and 3D photonic scanning measurements from which anatomical girths were extracted, enabling computation of body mass index (BMI), total fat, and visceral adipose tissue (VAT). On average, UK male offshore workers are now 8.1 years older, 3.1 cm taller, 13.9 kg heavier, and have greater girths than in 1984, which are > 97% attributable to increased weight, and < 3% to age difference. Mean BMI increased significantly from 24.9 to 28.1 kg/m2 and - of the contemporary sample - 18% have healthy weight, 52% are overweight, and 30% obese, representing an increase in overweight and obesity prevalence by 6% and 24%, respectively. Waist cutoffs identify 39% of the contemporary sample as healthy, 27% at increased health risk, and 34% at high risk. In conclusion, UK offshore workers today have higher BMI than Scottish men, although some muscular individuals may be misclassified by BMI. Girth data, particularly at the waist, where dimensional increase was greatest, together with predictions of total and visceral fatness, suggest less favorable health status in others

Kinematic and kinetic analysis of maximal velocity deadlifts performed with and without the inclusion of chain resistance.

The purpose of this study was to investigate whether the deadlift could be effectively incorporated with explosive resistance training (ERT) and to investigate whether the inclusion of chains enhanced the suitability of the deadlift for ERT. Twenty-three resistance trained athletes performed the deadlift with 30, 50, and 70% 1-repetition maximum (1RM) loads at submaximal velocity, maximal velocity (MAX), and MAX with the inclusion of 2 chain loads equal to 20 or 40% of the subjects' 1RM. All trials were performed on force platforms with markers attached to the barbell to calculate velocity and acceleration using a motion capture system. Significant increases in force, velocity, power, rate of force development, and length of the acceleration phase (p < 0.05) were obtained when repetition velocity increased from submaximal to maximal. During MAX repetitions with a constant resistance, the mean length of the acceleration phase ranged from 73.2 (±7.2%) to 84.9 (±12.2%) of the overall movement. Compared to using a constant resistance, the inclusion of chains enabled greater force to be maintained to the end of the concentric action and significantly increased peak force and impulse (p < 0.05), while concurrently decreasing velocity, power, and rate of force development (p < 0.05). The effects of chains were influenced by the magnitude of the chain and barbell resistance, with greater increases and decreases in mechanical variables obtained when heavier chain and barbell loads were used. The results of the investigation suggest that the deadlift can be incorporated effectively in ERT programs. Coaches and athletes should be aware that the inclusion of heavy chains may have both positive and negative effects on kinematics and kinetics of an exercise

The physiological effect of a 'climb assist' device on vertical ladder climbing.

Climb assist systems claim to reduce strain when climbing ladders; however, no research has yet substantiated this. The purpose of this study was to assess the physiological and psychophysical effects of climb assist on 30 m ladder climbing at a minimum acceptable speed. Eight participants (six male and two female) climbed a 30 m ladder at 24 rungs per minute with and without climb assist, and were monitored for heart rate (HR), O2 and rate of perceived exertion (RPE). All three variables decreased significantly (p < 0.05) with climb assist with O2 decreasing by 22.5%, HR by 14.8% and RPE decreasing by a mean of 2.3 units on the 10-point Borg scale. When descending the ladder O2 decreased by a mean of 42% compared to that ascending. At the minimal acceptable climbing speed climb assist decreases the physiological strain on climbers, as demonstrated by reduced O2, HR and perceived exertion

Non-imaging method: 3D scanning.

Three-dimensional body scanning is used to determine surface anthropometry characteristics such as body volume, segment lengths and girths. Three-dimensional scanning systems use laser, light or infrared technologies to acquire shape and software to allow manual or automatically extracted measures. Body posture during scanning is important to ensure accurate measures can be made from the images. The image vary depending on the configuration, resolution and accuracy of the scanner

A new waist-to-height ratio predicts abdominal adiposity in adults.

Our aim was to identify the best anthropometric index associated with waist adiposity. The six weight-status indices included body mass index (BMI), waist-to-hip ratio (WHR), waist-to-height ratio (WHTR), and a new waist-by-heigh

Effect of load positioning on the kinematics and kinetics of weighted vertical jumps.

One of the most popular exercises for developing lower-body muscular power is the weighted vertical jump. The present study sought to examine the effect of altering the position of the external load on the kinematics and kinetics of the movement. Twenty-nine resistance-trained rugby union athletes performed maximal-effort jumps with 0, 20, 40 and 60% of their squat 1RM, with the load positioned as follows: 1) on the posterior aspect of the shoulder using a straight barbell (SBJ); and 2) at arms length using a hexagonal barbell (HBJ). Kinematic and kinetic variables were calculated through integration of the vertical ground reaction force data using a forward dynamics approach. Performance of the HBJ resulted in significantly (p < 0.05) greater values for jump height, peak force, peak power and peak rate of force development, compared to the SBJ. Significantly (p < 0.05) greater peak power was produced during the unloaded jump compared to all trials where the external load was positioned on the shoulder. In contrast, significantly (p < 0.05) greater peak power was produced when using the hexagonal barbell combined with a load of 20% 1RM compared to all other conditions investigated. The results suggest that weighted vertical jumps should be performed with the external load positioned at arms length rather than on the shoulder when attempting to improve lower-body muscular performance

A biomechanical comparison of the traditional squat, powerlifting squat and box squat.

The purpose of this study was to compare the biomechanics of the traditional squat with two popular exercise variations, commonly referred to as the powerlifting squat and box squat. Twelve male powerlifters performed the exercises with 30, 50 and 70% of their measured 1RM, with instruction to lift the loads as fast as possible. Inverse dynamics and spatial tracking of the external resistance were used to quantify biomechanical variables. A range of significant kinematic and kinetic differences (p < 0.05) emerged between the exercises. The traditional squat was performed with a narrow stance, whereas the powerlifting squat and box squat were performed with similar wide stances (48.3 ± 3.8cm, 89.6 ± 4.9cm, and 92.1 ± 5.1cm, respectively). During the eccentric phase of the traditional squat the knee travelled past the toes resulting in anterior displacement of the system center of mass (COM). In contrast, during the powerlifting squat and box squat a more vertical shin position was maintained, resulting in posterior displacements of the system COM. These differences in linear displacements had a significant effect (p < 0.05) on a number of peak joint moments, with the greatest effects measured at the spine and ankle. For both joints the largest peak moment was produced during the traditional squat, followed by the powerlifting squat, then box squat. Significant differences (p < 0.05) were also noted at the hip joint where the largest moment in all three planes was produced during the powerlifting squat. Coaches and athletes should be aware of the biomechanical differences between the squatting variations and select according to the kinematic and kinetic profile that best match the training goals